Left–right asymmetry in the nervous system: the Caenorhabditis elegans model

2002 ◽  
Vol 3 (8) ◽  
pp. 629-640 ◽  
Author(s):  
Oliver Hobert ◽  
Robert J. Johnston ◽  
Sarah Chang
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Left Right Asymmetry

Behavioral Effects of Volatile Anesthetics in Caenorhabditis elegans

1996 ◽  
Vol 85 (4) ◽  
pp. 901-912 ◽  
Author(s):  
Michael C. Crowder ◽  
Laynie D. Shebester ◽  
Tim Schedl
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Time Course ◽  
Model Organism ◽  
Volatile Anesthetic ◽  
Volatile Anesthetics ◽  
Effective Concentration ◽  
Forward Genetics ◽  
C Elegans ◽  
Median Effective Concentration

Background The nematode Caenorhabditis elegans offers many advantages as a model organism for studying volatile anesthetic actions. It has a simple, well-understood nervous system; it allows the researcher to do forward genetics; and its genome will soon be completely sequenced. C. elegans is immobilized by volatile anesthetics only at high concentrations and with an unusually slow time course. Here other behavioral dysfunctions are considered as anesthetic endpoints in C. elegans. Methods The potency of halothane for disrupting eight different behaviors was determined by logistic regression of concentration and response data. Other volatile anesthetics were also tested for some behaviors. Established protocols were used for behavioral endpoints that, except for pharyngeal pumping, were set as complete disruption of the behavior. Time courses were measured for rapid behaviors. Recovery from exposure to 1 or 4 vol% halothane was determined for mating, chemotaxis, and gross movement. All experiments were performed at 20 to 22 degrees C. Results The median effective concentration values for halothane inhibition of mating (0.30 vol%-0.21 mM), chemotaxis (0.34 vol%-0.24 mM), and coordinated movement (0.32 vol% - 0.23 mM) were similar to the human minimum alveolar concentration (MAC; 0.21 mM). In contrast, halothane produced immobility with a median effective concentration of 3.65 vol% (2.6 mM). Other behaviors had intermediate sensitivities. Halothane's effects reached steady-state in 10 min for all behaviors tested except immobility, which required 2 h. Recovery was complete after exposure to 1 vol% halothane but was significantly reduced after exposure to immobilizing concentrations. Conclusions Volatile anesthetics selectively disrupt C. elegans behavior. The potency, time course, and recovery characteristics of halothane's effects on three behaviors are similar to its anesthetic properties in vertebrates. The affected nervous system molecules may express structural motifs similar to those on vertebrate anesthetic targets.

Presynaptic targets for acute ethanol sensitivity

2010 ◽  
Vol 38 (1) ◽  
pp. 172-176 ◽  
Author(s):  
Jeff W. Barclay ◽  
Margaret E. Graham ◽  
Mark R. Edwards ◽  
James R. Johnson ◽  
Alan Morgan ◽  
...  
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Alcohol Abuse ◽  
Synaptic Vesicle ◽  
Protein Interactions ◽  
Model Organism ◽  
Acute Exposure ◽  
Ethanol Sensitivity ◽  
Acute Ethanol ◽  
Specific Proteins

Acute exposure to ethanol is known to modulate signalling within the nervous system. Physiologically these effects are both presynaptic and postsynaptic in origin; however, considerably more research has focused primarily on postsynaptic targets. Recent research using the model organism Caenorhabditis elegans has determined a role for specific proteins (Munc18-1 and Rab3) and processes (synaptic vesicle recruitment and fusion) in transducing the presynaptic effects of ethanol. In the present paper, we review these results, identifying the proteins and protein interactions involved in ethanol sensitivity and discuss their links with mammalian studies of alcohol abuse.

scholarly journals Complex Cooperative Functions of Heparan Sulfate Proteoglycans Shape Nervous System Development in Caenorhabditis elegans

2014 ◽  
Vol 4 (10) ◽  
pp. 1859-1870 ◽  
Author(s):  
Carlos A. Díaz-Balzac ◽  
María I. Lázaro-Peña ◽  
Eillen Tecle ◽  
Nathali Gomez ◽  
Hannes E. Bülow
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Heparan Sulfate ◽  
System Development ◽  
Nervous System Development ◽  
Heparan Sulfate Proteoglycans

scholarly journals Stochastic left–right neuronal asymmetry in Caenorhabditis elegans

2016 ◽  
Vol 371 (1710) ◽  
pp. 20150407 ◽  
Author(s):  
Amel Alqadah ◽  
Yi-Wen Hsieh ◽  
Rui Xiong ◽  
Chiou-Fen Chuang
Keyword(s):  
Caenorhabditis Elegans ◽  
Molecular Mechanisms ◽  
Neurological Diseases ◽  
Calcium Signalling ◽  
Model Organism ◽  
Brain Asymmetry ◽  
C Elegans ◽  
Left And Right ◽  
Left Right Asymmetry ◽  
Neuronal Asymmetry

Left–right asymmetry in the nervous system is observed across species. Defects in left–right cerebral asymmetry are linked to several neurological diseases, but the molecular mechanisms underlying brain asymmetry in vertebrates are still not very well understood. The Caenorhabditis elegans left and right amphid wing ‘C’ (AWC) olfactory neurons communicate through intercellular calcium signalling in a transient embryonic gap junction neural network to specify two asymmetric subtypes, AWC OFF (default) and AWC ON (induced), in a stochastic manner. Here, we highlight the molecular mechanisms that establish and maintain stochastic AWC asymmetry. As the components of the AWC asymmetry pathway are highly conserved, insights from the model organism C. elegans may provide a window onto how brain asymmetry develops in humans. This article is part of the themed issue ‘Provocative questions in left–right asymmetry’.

scholarly journals Differential expression of five tRNA(UAGTrp) amber suppressors in Caenorhabditis elegans.

1988 ◽  
Vol 8 (9) ◽  
pp. 3627-3635 ◽  
Author(s):  
K Kondo ◽  
J Hodgkin ◽  
R H Waterston
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Gene Family ◽  
Development Stage ◽  
Base Change ◽  
Wild Type ◽  
Specific Manner ◽  
Flanking Sequences ◽  
Single Base Change ◽  
The Individual

Caenorhabditis elegans has 12 tRNA(UGGTrp) genes as defined by Southern analysis. In order to evaluate the function of the individual members of this multigene family, we sought to recover amber (UAG)-suppressing mutations from reversion experiments with animals carrying amber mutations in a nervous system-affecting gene (unc-13) or a sex-determining gene (tra-3). Revertants were analyzed by Southern blot, exploiting the fact that the CCA to CTA change at the anticodon creates a new XbaI site. Five different members of the tRNATrp gene family were identified as suppressors: sup-7 X, sup-5 III, sup-24 IV, sup-28 X, and sup-29 IV. All five suppressor genes were sequenced and found to encode identical tRNA(UAGTrp) molecules with a single base change (CCA to CTA) at the anticodon compared with their wild-type counterparts. The flanking sequences had only limited homology. The relative expression of these five genes was determined by measuring the efficiencies of suppressers against amber mutations in genes affecting the nervous system, hypodermis, muscle, and sex determination. The results of these cross-suppression tests showed that the five members of the tRNA(Trp) gene family were differentially regulated in a tissue- or development stage-specific manner.

scholarly journals A nervous system-specific subnuclear organelle in Caenorhabditis elegans

Genetics ◽  
2021 ◽  
Vol 217 (1) ◽  
Author(s):  
Kenneth Pham ◽  
Neda Masoudi ◽  
Eduardo Leyva-Díaz ◽  
Oliver Hobert
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Homeobox Gene ◽  
Cell Types ◽  
Nuclear Bodies ◽  
Loss Of Function ◽  
Cell Type ◽  
Cell Type Specificity ◽  
Splicing Speckles ◽  
Polycomb Bodies

Abstract We describe here phase-separated subnuclear organelles in the nematode Caenorhabditis elegans, which we term NUN (NUclear Nervous system-specific) bodies. Unlike other previously described subnuclear organelles, NUN bodies are highly cell type specific. In fully mature animals, 4–10 NUN bodies are observed exclusively in the nucleus of neuronal, glial and neuron-like cells, but not in other somatic cell types. Based on co-localization and genetic loss of function studies, NUN bodies are not related to other previously described subnuclear organelles, such as nucleoli, splicing speckles, paraspeckles, Polycomb bodies, promyelocytic leukemia bodies, gems, stress-induced nuclear bodies, or clastosomes. NUN bodies form immediately after cell cycle exit, before other signs of overt neuronal differentiation and are unaffected by the genetic elimination of transcription factors that control many other aspects of neuronal identity. In one unusual neuron class, the canal-associated neurons, NUN bodies remodel during larval development, and this remodeling depends on the Prd-type homeobox gene ceh-10. In conclusion, we have characterized here a novel subnuclear organelle whose cell type specificity poses the intriguing question of what biochemical process in the nucleus makes all nervous system-associated cells different from cells outside the nervous system.

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